The invention relates to a timber beam hanger and resulting beam connection as used in building construction.
It is well known to use fabricated or formed metal connecting components to interconnect timber beams used in building constructions. The term "timber beam" as used herein refers to a solid or one-piece timber beam, a glue-laminated timber beam, or so-called engineered wood products such as "Paralam" or Microlam" (trade-marks). Such fabricated connecting components reduce or essentially eliminate complex wood cutting which would otherwise be required to form inter-fitting portions of joints, for example cross-halving, mortice and tenon joints, etc. These metal components take many forms to enable a wide variety of beam connections to be easily accomplished, and are commonly termed "beam hangers". In most cases, the beam hangers have at least one pair of parallel side flanges and an interconnecting bottom flange which embrace outer surfaces of the beams and have openings to receive fasteners, for example nails, to pass therethrough so as to secure the beam to the hanger. In heavy duty applications, the fasteners can be heavy duty screws, or for added security, the fasteners can be bolts which pass through aligned openings in the beam and the flanges, and a threaded end of the bolt is secured with a conventional nut. In some architectural designs the beams are exposed in the room, and if hangers as above described are used, at least some of the flanges of the hangers are visible, and sometimes the fasteners are also visible and thus can be unsightly. Where fasteners or dowels are required to pass through aligned openings in the beam and flanges, close tolerance machining is usually required in both the beam and flanges to ensure a proper fit, further increasing cost of manufacturing and installation.
Beams are commonly supplied in many different sizes, and because a relatively close fit is required between a conventional beam hanger and the beam, a corresponding large number of beam hangers must be available to accommodate the wide range of beam sizes. This range of sizes increases costs of manufacturing and storing beam hangers, as well as complicating designs. Use of such hangers also requires relatively close tolerances to be maintained on dimensions of the beams to ensure a snug fit between flanges of the hanger.
U.S. Pat. No. 5,104,252 issued to Simpson Stong-Tie Company Inc. and in which the inventors are Colonias and Leak, discloses a hanger connection of a general type as described above. As can be seen, some hanger connections have relatively complex geometry, and spacings between some portions of the connections are critical to ensure a snug fit as above described, thus resulting in relatively costly hangers.
U.S. Pat. No. 5,253,945 (Hosokawa) discloses a connector for beams and posts which provides bending moment resistance and thus, for example, can be used to connect adjacent ends of two beams together so as to lengthen a beam. This is achieved by a relatively complex connection in which longitudinal tensile forces are transferred through a plurality of bolts which act on plate members to draw adjacent beam faces into intimate engagement with each other. This connection can also be used to connect a beam to a post so that the beam connection can resist moments.
End and side faces of the beams or posts must be machined to provide access openings for installing and adjusting the bolts which clearly requires accurate machining and careful adjustment during manufacturing and assembly.
U.S. Pat. No. 5,295,754 (Kato) discloses a beam connector which has a generally vertical web or hook plate having a pair of projections extending axially from an outer edge of the plate. The projections also have relatively complex geometry and are received in complementary openings in a vertical column or post, the openings having similar complex geometry which cooperates with the projections to retain the web or plate against the column. The web is retained within an elongated vertical slit within an end face of a beam and thus is shielded from view. However, bolts pass through the beam and are retained in complementary openings or slits within the web to prevent axial movement of the beam with respect to the web. While this patent discloses a hanger in which most of the hanger is shielded from view when installed, the hanger itself is relatively complex and costly to manufacture, and requires the production of complex openings in an adjoining vertical post, and thus is costly to instal. In addition, care must be taken to ensure that the web is installed accurately within the beam and the openings are located accurately within the post to ensure proper fitting, which further increases cost of installation.
U.S. Pat. No. 4,981,388 (Becken et al) discloses a timber joining system in which two intersecting members can be joined together with a bolt which passes at an inclined angle through one member to be received within a female threaded opening passing transversely through a cylindrical member fitted within a second member. This would appear to be more suitable for relatively small members, for example small pieces of wood, such as used in furniture.
To the inventor's knowledge, there is no timber hanger which can be essentially completely concealed within heavy timber beams, at least when viewed from underneath, which can be easily adapted to accommodate a wide range of beam sizes, and can be produced and installed at relatively low cost due to relatively wide dimensional tolerances for manufacture of the beam and hanger, and for installation purposes.